Monday, December 17, 2007

JEE Questions Ch.27 Aldehydes, Ketones

1. How will you convert
i) Acetone to 2-methyl-2-propanol
ii) Ethanal to 2-hydroxy-3-butenoic acid 1990

2. CH3COCH3-----base,catalyst---> ? -----acid,catalyst--> ? 1998

3.Benzene with one H substituted by CHO-----------K2Cr2O7, Conc.H2SO4--->?----PCl5--?----NH3----> ?-------P2O5---> ? 1986

4. Write the IUPAC name of CH2=CHCHO 1993

5. A ketone (A) which undergoes haloform reaction gives compound B on reduction. B on heating with conc. H2SO4 gives a compound (C) which forms monozonide(D). D on hydrolysis in the presence of zinc dust gives only acetaldehyde. Identify A,B,C,D. Write down the reactions involved. 1989

6. An alkene (A) on ozonolysis gives acetone and an aldehyde. The aldehyde is easily oxidized to an acid (B). When (B) is treated with bromine in the presence of phosphorus, it yields compound (C) which on hydrolysis gives an hydroxy acid (D). This acid can alos be obtained from acetone hy the reaction with hydrogen cyanide followed by hydrolysis. Identify the compounds A,B,C and D. 1991

7. An aldehyde, A (C11H8O) which does not undergo self aldol condensation gives benzaldehyde and two moles of B on ozonolysis. compound B on oxidation with silver ion gives oxalic acid. Idenity the compounds A and B. 1997

8. An organic compound A, C6H10O, on reaction with CH3MgBr followed by acid treatment gives compound B. The compound B on ozonolysis gives compound C, which in presence of a base gives 1-acetyl cyclopentene, D. The compound B on reaction with HBr gives compound E. Write structures of A,B,C,D and E. Show how D is formed from C. 2000

9. C6H5CHO + CH3COOC2H5-----NaOC2H5 in C2H5OH & heat------>? 1995

10. How many asymmetric carbon atoms are created during the complete reduction of benzil (PhCOCOPh) with LiAH4. Also write the number of possible stereoisomers of the product. 1997

11. Acetophenone on reaction with hydroxylamine hydrochloride can produce tow isomeric oximes. Write structures of the oximes. 1997

12. An alkene A(C16H16) on ozonolysis gives only one product B (C8H8O). Compound B on reaction with NaOH/I2 yields sodium benzoate. Compound B reacts with KOH/NH2NH2 yielding a hydrocarbon (C) C8h10. Write the structure of compound B and C. Based on this information two isomeric structures can be proposed for alkene A. Write their structures and identify the isomer which on catalytic hydrogenation (H2/Pd-C) gives a recemic mixture. 2001

13. The formation of cyanohydrin from ketone is an example of

a) Electrophyllic addition
b) Nucleophilic addition
c) Necleophilic substitution
d) Electrophilic substitution 1990

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